| Glucosamine (GlcN), is also known as amino sugar, a compound of glucose whosesecond hydroxyl replaced by Amino. GlcN has a widespread use in medical field andhealth care field. Glucosamine was currently produced by extraction and acidhydrolysis of chitin from shellfish waste. However, the production volume could belimited by the amount of raw material available. Besides, the production potentiallycarries the risk of shellfish protein contamination which seriously pollutes theenvironment and causes allergy of some people. In current research, it is a hotspot ofmicroorganism fermentation alternativing acid hydrolysis.In this paper, we introduced a method of constructing a genetically engineeredbacterium to produce glucosamine. Through analysising amino glucose metabolicpathway, we found two key enzymes which were glucosamine-6-phosphateacetyltransferase and Amino glucose6-phosphate synthase. Through Overexpressingbacillus subtilis glucosamine-6-phosphate synthase （Glms） and Saccharomycescerevisiae glucosamine-6-phosphate acetyltransferase (gnaI) in Escherichia coli,glucosamine and N-acetylglucosamine were produced by microbial fermentation.Dealing with weak acid, N-acetylglucosamine turned into glucosamine. Compared withmycelidium, production and expression of glucosamine-6-phosphate synthase andglucosamine-6-phosphate acetyltransferase were greatly improved.Through flask fermentation optimization, intracellular and extracellularglucosamine production respectively reached0.637g/L and4.585g/L at16h. And thecontrolled bacterium was only0.235g/L and0.562g/L. The total glucosamineproduction was5.222g/L in fermentation broth, and the controlled bacterium only0.797g/L. In fermentor, glucosamine and N-acetyglucosamine production even reached7.992g/L and3.501g/L respectively. It is a great improvement compared with thecontrolled bacterium and a great significance for fermenting glucosamine andN-acetyglucosamine. |
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